The subject of the present invention is a differential sampler circuit having two differential inputs and two outputs and including a voltage/current converter whose inputs are those of the sampler circuit and which has two outputs.
In the field of digital signal processing, and especially for digital television receivers, it is necessary to employ analog/digital converters whose sampling frequencies may attain 2 to 3 GHz.
In order to produce a sampler circuit, it is known to use a differential track-and-hold module such as described in the article by Messrs Vorenkamp and Verdaasdonk entitled "Fully bipolar, 120M sample/s 10-b track-and-hold circuits" published in the journal "IEEE Journal of solid-state circuits" n.degree. 7, of the month of July 1992. This module includes a switching cell composed of a transistor which, during the period of tracking of the input signal behaves as an emitter-follower so as to charge a recording capacitor, and which is reverse-biased during the holding period so as to retain as an output the signal which was recorded during the tracking period. The use of such an emitter-follower transistor as a switch gives rise to high-frequency oscillations. Moreover, this circuit exhibits a tracking period and then a holding period such that no conversion can take place during the tracking period. The performance of such a circuit is therefore limited in frequency.